![]() We run a couple of district competition hikes a year and despite requesting to the troops that they only enter competent walkers (we offer a training team with adult option) we without fail always get 1 team going off at a tangent. When I say lost its more like misplaced by less than a km, these aren't in the middle of nowhere style hikes. (I am a Hillwalking trainer\assessor for Scoutleaders) Lost hiking teams ? Teach them to navigate properly !!!! That is intended to strip out the GPS lat and long and transmit as Morse. The GPS capable Lost Model Locator PCB is about to be sent off, that uses a 28X2, and is about 25mm x 40mm. Not sure the Morse could be decoded automatically for a large enough distance for your application although at 15WPM you could read it by ear from a lot further away than the electronic decoding. ![]() From a suitable hilltop I was getting a direction reading from about 10KM away line of sight. As the frequency chosen was 434Mhz, there are plenty of readily available direction finding aerials, both ready made and DIY plans. The beacon tones change as you get nearer to the locator. You can get a direction using your body as a shield. It was designed to find a lost RC model using just a UHF tranciever as the location aid. If you have ever taken a modern comms receiver to bits, you will note that the differerance in circuitry compared to a typical wireless module such as the Hope RFM31 is significant, as is the cost.įor long range location the lost model locator I did would be a better choice. However I suspect a great deal of it is down to the extra sensitivity ot the UHF trancievers, they obviously use far more complex receiver circuitry. I have thought about that quite a bit, and the real answer is I dont know. The bits fit on a PCB 50mmx35mm, the charge for 10 of these boards delivered is just under £10. Just about to send the PCB off to ITeadstudio. I have shrunk the morse decoder quite a bit, but allowed for PIH components throughout. Most of the devices in Eagle I have made myself, its just easier than finding the exact part matches in the Libraries. ![]() I was an Electronic Design Enginner is the days of Z80s and 6502s etc, but way back then PCB design was 2 sheets of polyester film, transfers and black crepe tape for tracks. The transmitter now uses continuous PWM to output the Morse 'audio' tones, so a single delay parameter (the dit length) controls the Morse rate and already slows down to 15WPM for humans, and leaves 60WPM for psuedo telemetry decoded by a PICAXE. You can decode Morse through souncard software on a Netbook, but who want to carry a netbook around all the time ? However not everyone can read Morse, and I thought it would also be handy to get a running display of how high and how far away my planes were in flight, hence the portable decoder. I believed that Morse would by far offer the greatest search range, useful if your looking for someting lost, and this appears to be the case, data telemetry is very poor in comparison. ![]() The primary intention was always to transmit the GPS info as Morse numbers at about 15WPM, as this did not require any additional equipment to receive apart from an ear and a cheap UHF tranciever. This is all tied up with a Lost Model Locator I built that puts out GPS information. ![]()
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